kubernetes-sigs/gateway-api v0.4.0 on GitHub

API version: v1alpha2

This release contains significant breaking changes as we strive for a concise API. We anticipate that this API will be very similar to a future v1beta1 release.

The following changes have been made since v0.3.0:

Major Changes

The Gateway API APIGroup has moved from networking.x-k8s.io to gateway.networking.k8s.io. This means that, as far as the apiserver is concerned, this version is wholly distinct from v1alpha1, and automatic conversion is not possible. As part of this process, Gateway API is now subject to Kubernetes API review, the same as changes made to core API resources. More details in #780 and #716.
Gateway-Route binding changes (GEP-724): In v1alpha1, Gateways chose which Routes were attached using a combination of object and namespace selectors, with the option of also specifying object names. This resulted in a very complex config, that's easy to misinterpret. As part of v1alpha2, we're changing to:
- Gateways may specify what kind of Routes they support (defaults to same protocol if not specified), and where those Routes can be (defaults to same namespace).
- Routes must directly reference the Gateways the want to attach to, this is a list, so a Route can attach to more than one Gateway.
- The Route becomes attached only when the specifications intersect.
We believe this is quite a bit easier to understand, and still gives good flexibility for most use cases. GEP added in #725. Implemented in #754. Further documentation was added in #762.
Safer cross-namespace references (GEP-709): This concerns (currently), references from Routes to Backends, and Gateways to Secrets. The new behavior is:
- By default, references across namespaces are not permitted; creating a reference across a namespace (like a Route referencing a Service in another namespace) must be rejected by implementations.
- These references can be accepted by creating a ReferencePolicy in the referent (target) namespace, that specifies what Kind is allowed to accept incoming references, and from what namespace and Kind the references may be.
The intent here is that the owner of the referent namespace must explicitly accept incoming references, otherwise we can run into all sorts of bad things from breaking the namespace security model. Implemented in #741.
Attaching Policy to objects (GEP-713): This has been added so that we have an extensible mechanism for adding a cascading set of policy to Gateway API objects.
What policy? Well, it's kind of up to the implementations, but the best example to begin with is timeout policy.
Timeout policy for HTTP connections is highly dependent on how the underlying implementation handles policy - it's very difficult to extract commonalities.
This is intended to allow things like:
- Attach a policy that specifies the default connection timeout for backends to a GatewayClass. All Gateways that are part of that Class will have Routes get that default connection timeout unless they specify differently.
- If a Gateway that's a member of the GatewayClass has a different default attached, then that will beat the GatewayClass (for defaults, more specific object beats less specific object).
- Alternatively, a Policy that mandates that you can't set the client timeout to "no timeout" can be attached to a GatewayClass as an override. An override will always take effect, with less specific beating more specific.
This one is a bit complex, but will allow implementations to solve some things that currently require tools like admission control. Implemented in #736.
As part of GEP-713, BackendPolicy has been removed, as its functionality is now better handled using that mechanism. #732.
Removal of certificate references from HTTPRoutes (GEP-746): In v1alpha1, HTTPRoute objects have a stanza that allows referencing a TLS keypair, intended to allow people to have a more self-service model, where an app owner can provision a TLS keypair inside their own namespace, attach it to a HTTPRoute they control, and then have that used to secure their app. When implementing this, however, there are a large number of edge cases that are complex, hard to handle, and poorly defined - about checking SNI, hostname, and overrides, that made even writing a spec on how to implement this very difficult, let alone actually implementing it.
In removing certificate references from HTTPRoute, we're using the ReferencePolicy from GEP-709 to allow Gateways to securely create a cross-namespace reference to TLS keypairs in app namespaces. We're hopeful that this will hit most of the self-service use case, and even if not, provide a basis to build from to meet it eventually. GEP added in #749. Implemented in #768.
GEP-851, was a follow up on this change that allowed multiple Certificate Refs per Gateway Listener. This was implemented in #852.
The RouteForwardTo (YAML: routeForwardTo) struct/stanza has been reworked into the BackendRef (YAML: backendRef) struct/stanza, GEP-718. As part of this change, the ServiceName (YAML: serviceName) field has been removed, and Service references must instead now use the BackendRef/backendRef struct/stanza.

Small Changes

Extension points within match blocks from all Routes have been removed #829. Implements GEP-820. These extension points have been removed because they are currently not used, are poorly understood, and we don't have good use cases for them. We may consider re-adding them in the future.
Controller is now a required field in Gateway references from Route status. #671.
Header Matching, Query Param Matching, and HTTPRequestHeaderFilter now use named subobjects instead of maps. #657 and #681
#796 API Review suggestions:
- listener.routes has been renamed to listener.allowedRoutes
- The NoSuchGatewayClass has been removed after it was deprecated in v1alpha1
- * is no longer a valid hostname. Instead, leaving hostname unspecified is interpreted as *.
The scope field has been removed from all object references. #882
"Controller" has been renamed to "ControllerName" #839
"Admitted" condition has been renamed to "Accepted" and now defaults to an "Unknown" state instead of "False". #839
HTTPRequestRedirectFilter's Protocol field has been renamed to Scheme. #863
ImplementationSpecific match types in HTTPRoute's path, query, and header matches have been removed. #850
The "Prefix" path match type has been renamed "PathPrefix". #898

Small Additions

HTTP Method matching is now added into HTTPRoute, with Extended support: #733.

GatewayClass now has a 'Description' field that is printed as a column in kubectl get output. You can now end up with output that looks like this:

$> kubectl get gatewayclass
NAME       CONTROLLER                            DESCRIPTION
internal   gateway-controller-internal   For non-internet-facing Gateways.
external   gateway-controller-external   For internet-facing Gateways.

See #610 and #653 for the details.

Validation changes

Ensure TLSConfig is empty when the protocol is HTTP, TCP, or UDP #886
Ensure Hostname is empty when the protocol is TCP or UDP. #886
Listener ProtocolType now has validation. #871
HTTP Path match values are now validated for PathMatchExact and PathMatchPrefix match types. #894
TLS options keys are now subject to the same validation as Kubernetes annotations. #886
TLS options values now have a max length of 4096 characters. #886
Make MirrorFilter.BackendRef a required field when the mirror filter is used #837.

Clarifications

Updated guidance on how HTTP and TLS Route status should be populated when hostnames do not match. #859
Aligned path prefix matching with Ingress by clarifying that it is a prefix of path elements. #869
HTTP listeners may now be used for Cleartext HTTP/2. #879
Added clarification that implementation-specific TLS options MUST be domain-prefixed. #899

Documentation Updates

#782 : Restructure docs and split into versioned and unversioned
#777 : Fix typo
#765 : document multi-value headers as undefined
#761 : minor improvements to navigation on docs site
#760 : Remove references of vendor configurations in GatewayTLSConfig
#756 : Clarify docs on invalid serviceName
#755 : Document the supported kubernetes versions
#745 : Remove RouteTLSConfig requirement for gateway TLS passthrough.
#744 : automate nav for GEPs
#743 : Add READY and ADDRESS to gateway printer columns
#742 : Moving method match to v1alpha2 example
#729 : Adding suggested reasons for when conditions are healthy
#728 : Fixing wording in enhancement template
#723 : Clarifying Redirect Support levels
#756 : Clarify docs on invalid serviceName
#880 : Reworking Policy vs. Filter Documentation
#878 : Clarifying the fields that all Route types must include
#875 : Fix HTTP path match documentation.
#864 : Merging v1alpha2 concepts docs into unversioned docs
#858 : Fixing broken link to spec page
#857 : Adding missing references pages to docs navigation
#853 : docs: Use v0.4.0-rc1 in "Getting started with Gateway APIs" for v1alpha2
#845 : Fix markdown list formatting.
#844 : docs: add ssl passthrough note in FAQ
#843 : Add APISIX implementation
#834 : Fixes some broken links
#807 : docs: update multiple-ns guide for v1alpha2
#888 : Corrected broken getting started
#885 : Fix incorrect urls
#890 : Updating HTTPRoute docs for v1alpha2
#870 : Adding guidance on Kind vs. Resource in implementation guidelines
#865 : Route cleanup for v1alpha2 sig-network review

Tooling and infra updates

#766 : comment out the GEP notice
#758 : bump up mkdocs and deps
#751 : bump up deps to k8s v1.22
#748 : fix kustomize to install v1a2 crds
#747 : Cleaning up GEP Template
#889 : remove outdated version label
#883 : validating webhook cleanup
#872 : Remove duplicate validation from CRD & Webhook